There is no end to international interest in food and health. This growing interest has also spread to the domains of food and immunity. Abnormal immunomechanisms are the causes of such obstinate modern diseases as allergies such as hay fever, infectious diseases, and cancer. Additionally, in contemporary Japan, an extended economic downturn, irregular lifestyles, poor eating habits, mental stress, and the like are widespread causes of damage to immunomechanisms. Meanwhile, the prevention of such obsinate diseases has become possible through foods (ingredients). In particular, in Japan, where fewer children and an increasing average age are the trends, it is easy to imagine how future medical expenses could drain national coffers, and the concept of preventive medicine is assuming ever greater significance.
Immunoresponses can be divided into innate immunity and acquired (adaptive) immunity. Innate immunity, the former, refers to the immune system with which we are equipped at birth. Typical cellular factors responsible for organic defense mechanisms include phagocytes such as neutrocytes, macrophages, and dendritic cells. These cells identify, rapidly engage, and eliminate foreign bodies, such as microorganisms, with the help of fluid factors such as complements and lectins. Innate immunity not only plays a role in the early prevention of infection, but also plays a role in subsequent early induced reactions and differentiation of later-stage acquired (adaptive) immunity. That is, innate immunity plays an important role in orientation of the balance between cellular immunity and humoral immunity.
Cellular immunity of which main players are cytotoxic T cells (also known as “killer T kills”), macrophages, and the like, primarily function to prevent intercellular infection such as viral infection and the tumors caused by such infection. Humoral immunity controls the class switch of IgG1 and IgE antibodies in B cells, functioning to prevent infection by microorganisms that primarily proliferate in outside cells, such as protozoa, fungi, parasites, mycoplasma, pneumococci, and Escherichia coli. 
Cellular immunity and humoral immunity can be compared to the balancing of a seesaw. When this balance is disrupted for some reason (endogenous or exogenous), tipping toward cellular immunity, one becomes subject to autoimmune diseases such as insulin-dependent diabetes and chronic rheumatoid arthritis. Conversely, it has recently become clear that when this balance tips toward humoral immunity, various allergic disorders and cancer occur. That is, keeping these immunomechanisms well balanced is essential for maintaining bodily homeostasis.
Materials for food and drinks that regulate the balance of immunomechanisms in a normal state include those derived from fungi typified by mushrooms, yeasts and lactic acid bacteria, as well as seaweed, herbs, and the like (see Nonpatent Documents 1 to 7). These are called as biological response modifiers (BRMs), meaning that they have a regulatory effect.
The present inventors focused on fruit, a material that is readily available, inexpensive, and considered safe by consumers, and discovered that a fraction of which chief ingredient is polysaccharides contained in black currant juice activated macrophages in vitro (see Patent Document 1). Next, they discovered that it had a strong antitumor effect in mouse antitumor tests conducted in vivo, and named this polysaccharide fraction cassis polysaccharide (CAPS) (see Nonpatent Document 8).    [Non-Patent Document 1] Medical mushrooms as a source of antitumor and immunomodulating polysaccharides. (Appl. Microbiol. Biotechnol., 60, 258-274 (2002))    [Non-Patent Document 2] Antitumor activity and immune response of Mekabu fucoidan extracted from Sporophyll of Undaria pinnatifida. (In Vivo, 17, 245-250 (2003))    [Non-Patent Document 3] Antitumor potential of a polysaccharide-rich substance from the fruit juice of Morinda citrifolia (Noni) on Sarcoma 180 ascites tumour in mice. (Phytother. Res., 17, 1158-1164 (2003))    [Non-Patent Document 4]A polysaccharide, extract from Grifola frondosa, induces Th-1 dominant responses in carcinoma-bearing BALB/c mice. (Jpn. J. Pharmacol., 90, 357-360 (2002))    [Non-Patent Document 5] The anti-allergic effects of lactic acid bacteria are strain dependent and mediated by effects on both Th1/Th2 cytokine expression and balance. (Int. Arch. Allergy Immunol., 135, 205-215 (2004))    [Non-Patent Document 6] In vitro and in vivo anti-allergic activity of soy sauce. (Int. J. Mol. Med., 14, 879-884 (2004))    [Non-Patent Document 7] Clinical effects of Lactobacillus acidophilus strain L-92 on perennial allergic rhinitis: a double-blind, placebo-controlled study. (J. Dairy Sci., 88, 527-533 (2005))    [Non-Patent Document 8] Immunostimulatory Effects of a Polysaccharide-Rich Substance with Antitumor Activity Isolated from Black Currant (Ribes nigrum L.). (Biosci. Biotechnol. Biochem., 69 (11), 2042-2050 (2005))    [Patent Document 1] Japanese Unexamined Patent Publication (KOKAI) No. 2004-107660.
What is known in English as the “black currant” is known in Japanese as the “kurofusasuguri.” It is widely grown primarily in North America, Europe, and more recently, New Zealand. It is a material that is extremely well known, particularly in the liquor and confectionery industry.
However, the black currant juice that is the starting material for CAPS is more expensive than the juice of the common fruit. Thus, the actual development of products has been impeded by high cost and the fact that black currant juice is highly viscous, making it hard to handle.
Accordingly, an object of the present invention is to inexpensively provide a novel material derived from black currant juice that has a good antitumor effect similar to that of CAPS, is of low viscosity, and is easy to handle.
That is, an object of the present invention is to more inexpensively provide a material having good physiological activity by providing a material having greater physiological activity than CAPS in the form of a novel substance derived from black currant juice.
A further object of the present invention is to provide inexpensive and safe foods and drinks, particularly health foods and drinks, using the above novel material having good physiological activity.